Has anyone relocated their AFM to after the turbo? Does the spring tension need to be changed at all? I know that many people have done this in Japan so if anyone knows how its done id appreciate some input. Im going to do this to my car but im afraid that the pressurizd air after the turbo might affect the readings of the AFM. I hit 82% Airflow right now on my safc so after i relocate it, if everything is working right, i should be getting the same 82% or slightly more (bigger tid).

I dont belive you would modify it at all, you just have to re-adujust the safc because it will be reading the air differently



On a side note, have you considered the damage the afm could substain from being subjected to the heat of the compressed air?



where after the turbo are you moving it to? after turbo? after intercooler? just curious

I moved the afm today to right in front of the throttle body. After the BOV and intercooler. The intake temps shouldnt be too crazy and driveability is much imporved now. I did notice about 10% decrease in afm opening now that its after the turbo. I turned up the safc setting by 15% under boost and turned down my boost until the Innovative LM-1 gets here.

curious too, why would you do this?

Same here.

I was reading a hpi mag last night, it had the 'Garage Saurus' s14 silvia, full circuit race, and it had relocated afm after the intercooler, didnt say why though https://www.nopistons.com/forums/pub...1047683561.gif



"After the intercooler the charge air passes through a huge Infinity-type airflow meter and back to a huge custom plenum..."

this is a common practice in Japan acctually, the AFM before the turbo is considered a restriction, and the airflow can be altered, so they run an open face turbo and replumb the AFM after the turbo, it acctually meters the air better, and is not prone to false readings as much as before the turbo. There have been a few tests run in Option magazine to this, and there is a noticeable dyno power difference by doing it.

and there is no restriction when its after the turbo https://www.nopistons.com/forums/pub...1047683561.gif

There is less restriction after the turbo. Both before and after the turbo the same volume of air passes through the AFM "door". The difference is that after the turbo, the air is compressed; the molecules of air are squeezed closer together, so more of them can fit through the AFM door. This is how i see it anyways and the lower percentage of AFM door opening seems to back this up.



Another good thing is that i blew a hose off at 10 psi a few blocks away from my house. I was able to get home safely because it blew off before the AFM https://www.nopistons.com/forums/pub...DIR#>/wink.png Try that on a car with an AFM before the turbo.



Also, the car doesnt get rich and hesitate/jerk between mid throttle shifts and when i let off the throttle (mostly did this at mid throttle, never at WOT) with an atmosphere vented BOV.

I was boosting 15 psi and never had a problem with it hesitating or jerking, even with my type-s BOV



If you are getting a lower percentage of the AFM open, then that means that it is closed more, so less air is able to flow through, therefore, more restrictive and your ECU would see that you have less air so it will lean it out more. I assume thats why you have the SAFC to correct that.



And I am also curious, where is the room to mount this beast.

Man, this is a pretty crazy mod if you dont have a fromt mount then. I just cant see that being better flow with the TMIC there also. I can understand it not jerking or hesitaing or whatever when you shift if you have a vented bov because you will get a false reading. But as I stated, never had a problem before.



I also modified my AFM a little bit. I did an old supra trick to raise the fuel cut on them. Its kinda hard to explain, but there is a screw that is used to block a passage that avoids the flap all together. If you drill the cap over this screw and screw it out, you have a path that avoids the flap all together. I dont know if this had an effect since I do not have it anymore.



Hell, I made a AFM simulator that had an input from a MAP sensor and converted that to a AFM signal. It worked on the breadboard when it was hooked up to my car, just never finished it because I blew my ECU when I accidently crossed a wire. But that right there would eliminate the need for the AFM all together. The only downside to this is that you need a AFM converter and a full range TPS sensor. So you need to get that from a S5 if you have a S4.

How did you make the harness wires longer?



Have any pics?

I cut the harness and soldered extension wires for each wire, then loomed it and taped it. My harness is kinda cut up anyways so i dont care about cutting it. The best way would be to make an extension using the female afm harness plug from a spare harness on one end and a male plug on the other, that way its plug and play.



I'll try to take some pics at a friends house later on this week.



So far i only hit it in 1st gear to redline because im not sure how the change affected the afm. Before this i had a 2.25" tid with the afm in it. Now i have a 3" TID with one 90" bend in it. Both were cold air. Before in 1st gear i would get 6psi from 4k to redline. Now i get 5 psi at 3500rpm and 11 psi at 4000rpm at which point i break loose and have to shift pretty much right away to keep things under 7500rpm, hard to say if it keeps 10psi to redline but seems like it does.

With a TMIC, I still see it as being more of a restriction after the turbo..that's just me.



Also, how are you getting "cold air" to your TID? Is the filter relocated in front of the radiator as I've seen before..or ??



Please get some pics as I'm a little confused still about the entire setup and how it flows...

I have a stock S5 intercooler front mounted and yes, the filter is in front of the rad.

Got ya..I thought you still had the intercooler in the stock location.

so is their a downside to this mod? harm to afm? anything? will an s5 afm work on an s4?

The S5 and S4 are different. To use the S5, you need to repin it or something like that. And also, the S5 I believe is to be more of a restriction because it doesnt allow a direct path of air, but it diverts the air around a cone, not like the flap that opens right up to the other side.



The only thing that will hurt the AFM would be the heat. The sotck IC can only do so much, so the air will still be hot. It would mainly hurt the readings. Since metal expands when its heated, the variable resistor inside will expand also (kinda hard to explain how the inside of the AFM works), so it will give a higher voltage than what it should be reading. Depending on where the AFM is mounted can increase the reliabilty of the reading. I dont know how much it can be off, I dont have one around here anymore so I cant do any testing. It could be minimal, or it could be alot.



The only downside that I see from this setup is that you need to run some crazy piping if you are using the TMIC. If you have a FMIC, then its easier, but if you have a FMIC, then most people have a standalone so you dont need the AFM.

every car in the option mags has the afm moved, they really like to do that

sounds like a headache for no horsepower to me but i do see where it could be helpful for better readings and running better or somethin to that matter.